1. Field of the Invention
This invention concerns improvements relating to the operation of systems for raising and setting back aircraft arresting gears.
At present, on take-off and landing strips or runways, these arresting gears commonly have a net adapted to be raised in front of the aircraft in case of emergency, or alternatively a cable or wire extending across the strip in the case of aircraft equipped with a special cross-head.
It is the object of the present invention to widen the field of possible use of a rectractible bracket system for a crossing cable.
2. Description of the Prior Art
The most popular systems employed for this purpose involve pulling back the cable into a channel provided in the runway, so that the cable does not constitute an obstacle when aircrafts are passing and may be restored to its raised position for being caught, in case of emergency, by the cross-head of an aircraft.
The pulling back of the cable is obtained by disposing within the runway a plurality of rams (about 15 to 20 according to the runway width) which are individually fed with compressed gas from tanks disposed at one side of the runway.
Moreover, as the cable raising takes place, a linkage system causes the cable supports to move laterally for preventing the cable staying vertically above its housing in the runway so as to avoid inadvertent pulling back of the cable whilst an aircraft is passing with its cross-head in lowered position.
The rams must be perfectly aligned within the runway, which involves considerable foundation work, and must correctly work whatever the climatic conditions and the cleanness conditions may be. It is understood that such a system requires considerable and careful maintenance as well as the equipping of each ram with control instruments allowing to check that the crossing cable is in a correct position when an aircraft having a lowered cross-head arrives.